Narrative:

At 35000' first officer noticed the slats disagree light flicker on momentarily. At the same time ATC told us to descend to FL330 and pilot's discretion to FL240 and to cross 15 mi north of chattanooga at that altitude. The first officer queried me on the clearance and I repeated it correctly to him but when he said we'd have to hustle to make it down to that altitude in time I did not know he had in mind 15000' as a clearance altitude. At that very time in our descent toward chattanooga the slat overspd warning came on with a brief flicker of the slat disagree light. We had no actual control problem with the aircraft but this was the third time for this occurrence in 2 days on this aircraft and so being close to a major maintenance base (nashville) and being just mins from landing there I got on company frequency to call in this and one other maintenance write-up. Company radio was having trouble receiving my transmission and asked that I call closer in. Coming back to ATC frequency a new controller was asking us our altitude. I looked at the altitude, FL200, and told the first officer to level off. I asked the controller for a clearance altitude. He gave us 19000'. It is still not clear to me whether we were given a clearance to 15000' perhaps while I was talking on company frequency or that the 15 mi north clearance was taken for a 15000' altitude clearance initially. Note: after writing the above, the first officer told me that the controller asked him on initial contact if we were climbing to FL240 which means he had been told by the previous controller to expect us at FL240. The first officer is new in the aircraft having come from duty as a widebody transport F/east. Supplemental information from acn 151216. I set and armed 15000' in the altitude alert window. The captain was busy talking to maintenance and did not notice the error.

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Original NASA ASRS Text

Title: ALT BUST.

Narrative: AT 35000' F/O NOTICED THE SLATS DISAGREE LIGHT FLICKER ON MOMENTARILY. AT THE SAME TIME ATC TOLD US TO DSND TO FL330 AND PLT'S DISCRETION TO FL240 AND TO CROSS 15 MI N OF CHATTANOOGA AT THAT ALT. THE F/O QUERIED ME ON THE CLRNC AND I REPEATED IT CORRECTLY TO HIM BUT WHEN HE SAID WE'D HAVE TO HUSTLE TO MAKE IT DOWN TO THAT ALT IN TIME I DID NOT KNOW HE HAD IN MIND 15000' AS A CLRNC ALT. AT THAT VERY TIME IN OUR DSNT TOWARD CHATTANOOGA THE SLAT OVERSPD WARNING CAME ON WITH A BRIEF FLICKER OF THE SLAT DISAGREE LIGHT. WE HAD NO ACTUAL CTL PROB WITH THE ACFT BUT THIS WAS THE THIRD TIME FOR THIS OCCURRENCE IN 2 DAYS ON THIS ACFT AND SO BEING CLOSE TO A MAJOR MAINT BASE (NASHVILLE) AND BEING JUST MINS FROM LNDG THERE I GOT ON COMPANY FREQ TO CALL IN THIS AND ONE OTHER MAINT WRITE-UP. COMPANY RADIO WAS HAVING TROUBLE RECEIVING MY XMISSION AND ASKED THAT I CALL CLOSER IN. COMING BACK TO ATC FREQ A NEW CTLR WAS ASKING US OUR ALT. I LOOKED AT THE ALT, FL200, AND TOLD THE F/O TO LEVEL OFF. I ASKED THE CTLR FOR A CLRNC ALT. HE GAVE US 19000'. IT IS STILL NOT CLR TO ME WHETHER WE WERE GIVEN A CLRNC TO 15000' PERHAPS WHILE I WAS TALKING ON COMPANY FREQ OR THAT THE 15 MI N CLRNC WAS TAKEN FOR A 15000' ALT CLRNC INITIALLY. NOTE: AFTER WRITING THE ABOVE, THE F/O TOLD ME THAT THE CTLR ASKED HIM ON INITIAL CONTACT IF WE WERE CLBING TO FL240 WHICH MEANS HE HAD BEEN TOLD BY THE PREVIOUS CTLR TO EXPECT US AT FL240. THE F/O IS NEW IN THE ACFT HAVING COME FROM DUTY AS A WDB F/E. SUPPLEMENTAL INFO FROM ACN 151216. I SET AND ARMED 15000' IN THE ALT ALERT WINDOW. THE CAPT WAS BUSY TALKING TO MAINT AND DID NOT NOTICE THE ERROR.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.